Production of anthraquinone derivatives



-vl etented Sept. 230, i024 JQHN H. QAG'HS QF NILMINGTON, DELAWARE, AND VAPIAN S. 'BABASINIAN, OF SOUTH BETHLEHEDI, PENNSYLVANIA, ASSIGNGRS TO E. I. DU PONT DE NEMOURS 6a GOZVIPAINY, F 'WILMINGTON, DELAWARE, A GGRLEORATION OF DELAWARE.

PRODUCTION 0E ANTHBAQUINONE DERIVATIVES.

No Drawing.

To all whom it may concern:

Be it known that we, JOHN H. SACHS and VAHAN S. BABASINIAN, citizens of the United Stateaand residents of lvilmington,

county of New (lastlmfitate of Delaware,

and South Bethlehem county of Northampton, State of Pennsylvania, respectively; have invented a certain new and useful Production of Anthraquiuone Derivatives,

of which the following is a specification.

This invention relates to the oxidation of the product obtainable by fusing betazunino-anthraquinone with potassium nitrate and hydroxide and treating the resulting anthraquinone derivative with sodium hydrosulphite, and comprises'sub'jecting said product to the action oi? air or other suitable oxygencontaining gas in the presence of an acid.

lhe product Which is to be oxidized in the manner above outlined has most probably the following graphical formulaz and the product resulting from the oxidation. has most probably the formula:

an of its sodium salt, may be suspended in a dilute solution of a mineral acid, such. for i example as hydrochloric, nitric, or sulphuric acid, and air blown into the mixture While maintaining" the latter at a temperature of from about 60 to 90 C. until the oxidation is completed.

()ur process may be illustrated more in implication filed fieptember 25, 1920. Serial No. 412,819.

detail by the following example: 10 pounds of the sodium salt of the leuco derivative of N-dihydro-l,2-1',2-anthraqu.inone-azine (said leuco derivativeboing the same as the reduced form of product A. described in Patent 724,789) are suspended in about 500 pounds of a 6% solution of sulphuric acid, and the mixture then brought to a temperature of about 70 C. Air is then blown into the liquid, While maintaining the latter at about 70 C. for about one hour or until the oxidation is completed. The suspension is then filtered and the press cake, composed chiefly of N-dihydro-1,2-1,2-anthraquinone-azine, is washed with Water until free from acid.

The strength of acid used may vary considerably, although We prefer an acid of from 5 to 10% strength. The amount of sulphuric acid solution for 10 pounds of the sodium salt may be more or less than 500 pounds, an amount between 4:00 and 1000 pounds being preferred. We may for instance, suspend 10 pounds of the sodium salt'in from 600 to 1400 pounds of 7% hydrochloric acid, the treatment with air beingcarried out While the solution is at a temperature of 7080 C.

The advantages of this method of oxida tion over oxidation in alkaline or neutral solution are as follows:--

, (1) During the fusion, iron and other impuritiesare introduced into the melt. These are removed by the oxidation in acid solution, being soluble in this medium.

(2) The filtration of the product which results on oxidation in neutral or alkaline solution is very difiicult, Whereas the filtration is very easy when the oxidation is carried out in dilute acid.

3) The oxidation time in neutral or alkaline solution is live to six hours, Whereas in dilute acid the time is less than one hour.

The N dihydro-lfi-l,2'-uuthraquinone azine obtained in the above described manner is an intermediate in the manufacture of dyes of the anthraquinone series.

grouping:

Our new process of oxidation in an acid medium may also be employed to produce the homologs and N-alkyl derivatives of the above named azine from their corresponding leuco derivatives all of which contain the following atomic grouping:

I i I Q /k/\ O/V\ We claim 1. The process of producing an anthraquinone derivative which comprises oxidiz- 11 1n the presence oi an acid the leuco derivative of a product obtainable by fusing with potassium hydroxide and potassium nitrate.

The process of producing an anthraquinone derivative which comprises passing air into a dilute solution of a mineral acid containing in suspension the leuco derivative of a product obtainable by fusing betaamino-anthraquinone with potassium hydroxide and potassium nitrate.

i. The process of producing an anthraquinone' derivative which comprises passing air into aclilutc solution of sulphuric acid maintained at a temperature between and and 90 C. and containing in suspension the leuco: derivative ofauproduct obtainable by fusing beta-amino-anthraquinone with potassium hydroxide and potassium nitrate.

5. The process of producing an anthraquinone derivative which comprises oxidizing in the presence of an acid a substance whose molecule contains the following atomic 6. The process'of producing an anthrastance whose molecule contains the following atomic grouping:

7. The process of producing an anthraquinone derivative which comprises passing air into a mineral acid solution of from about 5 to 10% strength maintained at a temperature of between 60 and 90 C. and containing a substance whose molecule contains the following atomic grouping:

8. The process of producing N-dihydro- 1,2,1,2-anthraquinone-azine which coinprises suspending 10 parts of the leuco derivative of said azine in from about 400 to 1000 parts of sulphuric acid of about 6% strength, and passing air into the resulting suspension, while maintaining it ata temperature oi about (1., until oxidation of the leuco compound is substantially completed.

9. The process of producing an anthraquinone derivative which comprises suspending the sodium salt of the leuco derivative of N-dihydro-LQJ,2-anthraquinone-azine in a dilute solution of a strong mineral acid, and subjecting the suspended-leuco derivative to oxidation.

10. The process of producing an anthraquinone derivative which comprises suspending the sodium salt of the leuco derivative of N-dihyd1'o-1,2,1',2'-anthraquinone-azine in a-dilute solution of a strong mineral acid, and passing air through the resulting suspension until oxidation of the leuco derivative has occurred to the desired extent.

11. The process of producing an' anthra quinone derivative which comprises'suspending 10 parts of the sodium salt of the leuco derivative of N-dihydro-1,2,1',.2'-anthraquinone-azine in from about 400 to IOOOparts of a dilute solution of sulphuric acid pref erably of from 5 to 10% strengtlnaud sub' jecting the suspended leuco derivative to oxidation n testimony whereof we afiix oursigna tures.

JOHN H. SACHS. VAHAN S. BABASI'NI.:\N. 

